Your IP must modify IP GETSUPPORT to return support for IP_SUPPORT_JOIN_ORDER_SELECTION.
You can update the support array if the IP GETSUPPORT function uses the support array, or you can modify the IP GETSUPPORT function to enable the support for join order selection.
Updating the support array
IP_SUPPORT_JOIN_ORDER_SELECTION must be set to 1 in the support array to indicate that the IP supports join order selection.
Using the GETSUPPORT function
The IP GETSUPPORT function must return TRUE for IP_SUPPORT_JOIN_ORDER_SELECTION.
Note: If IP GETSUPPORT does not indicate support for IP_SUPPORT_JOIN_ORDER_SELECTION, OpenAccess SDK returns an error for a query with a join order.